Gartman argued that coal was simply too big to ignore, being used to generate an estimated 40 percent of electricity needs in the United States and worldwide.

"If you look at that sort of thing and think that you're going to expect or going to get continued global economic growth— and I think that you are—then one of the cheapest entities out there has to be coal," he said.

Without naming specific stocks, Gartman noted that many coal stocks were off 90 percent from their highs "and over the course of the last 10 months have built what looks to be reasonably good bases."

"It is a long-term leap on continued economic growth," he said. "Buy four or five of them. Two of them probably will go out of business. Two of them will probably double or triple, and one of them may be a 10-bagger after all the smoke clears. That's probably what will end up happening."